Illuminated switch means



June 30, 1970 I. J. GUBERMAN 3,513,336

ILLUMINATED SWITCH MEANS Filed Aug. 27, 1968 INVENTOR If? /V J. GUBERMA/V United States Patent O 3,518,386 ILLUMINATED SWITCH MEANS Irwin J. Guberman, Waltham, Mass., assignor to Raytheon Company, Lexington, Mass., a corporation of Delaware Filed Aug. 27, 1968, Ser. No. 755,682 Int. Cl. Hlh 9/18 US. Cl. 200-167 3 Claims ABSTRACT OF THE DISCLOSURE Illuminated switch means comprising a fiber optic harness including a plurality of fiber optic elements having a common end located adjacent a common sourceof illumination and respective opposite ends disposed adjacent respective transilluminative actuating portions of respective illuminated switches.

BACKGROUND OF THE INVENTION This invention relates generally to illuminated control devices and is more particularly concerned with illuminated switches.

Illuminated switches are used in control panels frequently to provide means for quickly locating a particular switch in an array of control devices. A small lamp is usually located in the body of the illuminated switch for directing light upon the actuating portion of the switch. Illuminating the front surface of the switch also provides means for identifying the switch. Thus, printed information on the front lens of a push-button switch is outlined and made clearly legible by a small lamp located in the switch behind the lens. Illuminated switches also include the lever type wherein a transparent or translucent lever emits a soft glow of light from a small lamp located in the body of the switch adjacent the rear of the lever. Formerly, illuminated switches required a plurality of lamps and color filters to indicate the various operating positions of the switch. However there are illuminated switches commercially available now which position the various color filters in front of a single lamp to indicate the respective operating positions of the switch.

Although recent innovations have considerably reduced the number of lamps required for an array of illuminated switches, the lamps still require frequent attention. Occasions often arise where at least one lamp in the array of switches needs replacement. For some types of illuminated switches, the lamps are accessible only from the rear of the control panel which cannot .be easily reached in all cases. Furthermore, the dense wiring which connects the contacts of the switches to respective circuits presents an obstacle when trying to extract a lamp from the rear of a particular switch which is located in an array of switches. In other types of illuminated switches, the lamp is accessible from the front of the control panel but only after the face of the associated switch has been disassembled. In some switches, the .lamp is located in a deep recess and a special tool is required for removing the lamp. Other types of illuminated switches have face plates which swing outward carrying the small lamps away from the switch body for easy access and replacement. However, this type of switch is comparatively expensive and the wiring to the lamps in the pivotable face plate is subject to early failure due to fatigue. Thus, a need clearly exists for an inexpensive solution to the problem of replacing defective lamps in illuminated switches without dismantling the switch or requiring special tools to do so.

In instances where a wide variety of color filters are needed to indicate the various operating positions of a switch, dark color filters, such as green or amber, must,

3,518,386. Patented June 30, 1970 "ice of necessity, be used. However, the quantity of light emitted by the small lamps in the associated switches may not be great enough to clearly highlight these darker colors. Thus, the operating positions of all the switches in the array will not be clearly visible at a glance. This problem is further aggravated by any printed information on the face plate of the switch. In some push-button switches, the printed information is not disposed on the face plate of the switch but on a removable glass insert located behind the face plate. Thus, the light from the small lamp is required to penetrate two thicknesses of glass in order to outline printing which may be densely disposed on the glass insert. The quantity of light cannot be increased by increasing the size of the lamp because the compact interior of the switch cannot accommodate a larger lamp. An alternative solution would be to obtain a lamp of the same size as the conventional lamp but which provides light of greater intensity. However, lamps of this type are more expensive and present a procurement problem. It would be highly desirable to increase the quantity of light wherever necessary without increasing the size of the light source in the body of the switch.

Even without increasing the quantity of light, thermal problems may develop due to the lamp being located in the body of the switch. Generally, panel-mounted switches of the lever type are provided with thin, metallic leaf-spring contacts which are disposed in close spaced relationship in order to reduce response time. Radiant heat from the filament in the lamp can cause thermal elongation of the leaf springs which will result in distortion and malfunctioning of the switch. Therefore, the lamp is usually located in a deep metallic socket which shields the leafspring contacts and provides a heat sink for the heat produced by the incandescent filament. An ideal solution to this thermal problem would be a source of light that does not have an objectionable amount of radiant heat associated with it.

SUMMARY OF THE INVENTION Accordingly, this invention provides a means of illuminating a plurality of switches by a single light source which is easily accessible for rapid replacement, which may be exchanged for a larger size without affecting the interiors of the respective switches and which does not produce objectionable radiant heat within the bodies of the respective illuminated switches. The present invention includes a fiber optic harness comprising a plurality of fiber optic elements having a common facing at one end adjacent a single suitable light source which is conveniently located, and opposite ends disposed adjacent actuating portions of respective switches whereby light transmitted from the common light source by the respective optic elements illuminates transilluminative material in the actuating portions of the respective switches and also outlines any printed information disposed thereon.

BRIEF DESCRIPTION OF THE DRAWING For a better understanding of this invention, reference is made to the accompanying drawing wherein:

FIG. 1 is a rear fragmentary elevational view of a control panel which embodies the invention;

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1 looking in the direction of the arrows; and

FIG. 3 is an elevational view, partly in section, taken along line 3-3 of FIG. 1 looking in the direction of the arrows.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, wherein like characters of reference designate like parts throughout the several views, there is shown in FIG. 1 the rear side of a control panel having an L-shaped bracket 12 mounted thereon by conventional means, as by machine screws 14 for example. A threaded sleeve 16 having one end attached to a light socket 18 is passed through an aperture (not shown) in bracket 12 and a nut 20 is threaded onto the opposite end of sleeve 16. Nut 20 is tightened against bracket 12 to hold one end of socket 18 firmly against the opposite side thereof. A lamp 22 is mounted in the opposite end of socket 18 to bear against contacting surfaces therein which are connected to wire leads 24 and 26. Wire lead 24 passes insulatingly through sleeve 16 and is connected at the opposite end to one side of a toggle switch 2-8. The other side of toggle switch 28 is connected to a metallic prong 32 of electrical plug 30 by means of wire lead 34. Wire lead 26 passes insulatingly through sleeve 16 and is connected at the opposite end to the other metallic prong 36 of plug 30. Electrical plug 30 is adapted to be inserted into a suitable electrical outlet for supplying electrical energy to lamp 22. Toggle switch 28 is provided with a lever (not shown) which protrudes through an aperture (not shown) in panel 10 and extends outwardly from the front side thereof for convenient manipulation when opening or closing the circuit to lamp 22.

A plurality of switches 40 are mounted on panel 10 and, as shown more clearly in FIGS. 2 and 3, have respective levers 42 which protrude through respective apertures 44 in panel 10 to extend outwardly from the front side thereof. Although the foregoing description refers to a single switch, it is applicable to each switch of the array shown in FIG. 1. A frame 46 surrounds the aperture 44 and s secured to the front side of panel 10 by means of screws 48 which also secure a support bracket 50 to the rear side of panel 10. An aperture 52 in bracket 50 is aligned with the aperture 44 in panel 10 and is provided with bearings in the opposing sides thereof which rotatably support the journal ends of a metallic rod 54. Rod 54 passes transversely through a thickened portion of lever 42 and is fixedly attached thereto, thereby pivotally supporting lever 42 in the opening 52 of bracket 50. The inner end of lever 42 is tapered into the shape of a truncated wedge and a color filter 56 is afiixed to the squared end of the wedge. Respective color filters 58 and 60 are affixed to the opposing broad surfaces of the wedge adjacent the squared end thereof. Lever 42 is made of a transilluminative dielectric material, such as nylon for example, which has the property of being transparent or translucent when exposed to light, and is often provided with an internal cavity having respective openings adjacent the respective color filters 56, 58 and 60. A dielectric rod 62 passes transversely through the wedge end of lever 42, adjacent the squared end thereof, and rotatably supports respective dielectric rollers 64 and 65 on the respective ends thereof. Roller 64 is disposed between the opposing sloped ends of respective leaf spring contacts 66 and 68 which are disposed in a tier of contacts 70 on one side of switch 40, as shown in FIG. 1. Roller 65 is disposed between the opposing sloped ends of respective leaf spring contacts 72 and 74 which are disposed in a tier of contacts 76 on the other side of switch 40. The contact tiers, 70 and 76 respectively, are insulatingly supported on respective opposite sides of switch 40 by means of interleafing, dielectric spacers 78 and screws '80. In the tier 70', respective contact pads on the lower side of leaf spring 66 and the upper side of leaf spring 68 are normally bearing against respective raised contacts on respective leaf springs 82 and 84. In the tier 76, respective contact pads on the lower side of leaf spring 72 and the upper side of leaf spring 74 are normally bearing against raised contacts on respective leaf springs 86 and 88. When the outer end of lever 42 is pushed downward, the inner end thereof travels in an upward direction and respective rollers 64 and 65 force respective leaf springs 66 and 72 to break contact with respective leaf springs 82 and 86 and to make contact with respective leaf springs 90 and 92. The sloped ends of the respective leaf springs 66 and 72 bearing against the peripheries of the respective rollers 64 and 65 lock the lever 42 in the described operating position until the outer end of lever 42 is manipulated. Similarly when lever 42 is pushed upward from the nor mal position, the inner end thereof travels in a downward direction and respective rollers 64 and 65 force respective leaf springs 68 and 74 to break contact with respective leaf springs 84 and 88 and to make contact with respective leaf springs '94 and 96. The ends of the respective leaf springs remote from the aforementioned contacting ends are provided with means (not shown) for attaching respective wires thereto. However, such wiring has not been shown in the drawing for purposes of clarity.

A generally Z-shaped bracket 98 has the lower flanged end attached to support bracket 50 by conventional means, as by welding for example, and the upper flanged end thereof secured to a dielectric frame 100 by any convenient means, as by bonding with an epoxy cement for example. Frame 100 is supported by bracket 98 in longitudinal alignment with lever 42 and in close spaced relationship with the inner end thereof. One end of a fiber optical element 102 faces the squared end of lever 42 when the lever is in the normal position, and is held thus disposed by any convenient means, as by bonding with epoxy adhesive, for example. The fiber optic element 102 is threaded through an aperture 103 in support bracket 50 and, as shown in FIG. 1, is routed into an optical harness 104. The respective fiber optics elements 102 from the respective switches 40 are formed into a common bundle which terminates at the other end in a common facing 106. The common faced end 105 of fiber optic harness 104 is encircled by a metallic ring (not shown) which is press fitted into an aperture (not shown) in L-shaped bracket 108. Bracket 108 is located adjacent lamp 22 and is secured to the rear side of panel 10 by screws 110. Bracket 108 holds the common faced end 106 of fiber optic harness 104 so that the common end is facing the lamp 22. Lamp 22 may be coated with a reflective paint and have an aperture adjacent the common faced end 106 of fiber optic harness 104. Alternatively, lamp 22 may be covered by a shield of reflective metal which is provided with an aperture adjacent the common faced end 106 of fiber optic harness 104. These and other means may be used to direct the light emitted by lamp 22 into the open ends of the optical fibers which form the common faced end 106 of fiber optics harness 104.

Each fiber optic element 102 comprises a bundle of optical fibers enclosed by a protective sleeve, as is well known. Light from the lamp 22 enters the adjacent ends of the optical fibers and travels with minimal losses through these flexible conduits by means of total internal reflection. Thus, substantially all of the light entering the ends of the respective fiber optic elements 102 adjacent lamp 22 will exit from the opposite ends thereof and impinge on the adjacent ends of the respective levers 12. When the levers 12 are in normal operating positions, light from the adjacent ends of the optical elements 102 passes through respective color filters 56 and into the levers 42. Thus, the levers 42 will glow with light having the color of the respective filters 56 and thereby indicate that the switches 40 are in normal operating positions. Similarly, when any one of the levers 22 is pressed downward, light from the adjacent end of the optical elements 102 enters the lever 42 through color filter 58; and when a lever 42 is pushed upward, light from the respective fiber optic element 102 enters the lever 42 through filter 60.

Optical fibers having peak transmission in the upper or central region of the visible spectrum can be chosen for the fiber optic elements 102. Thus, transmission of infrared radiation can be kept to a minimum and light with only a minor amount of radiant heat from the filament in lamp 22 will be conducted to the respective switches 40. Consequently, the possibility of thermal distortion occurring in the respective switches 40* is reduced to a minimum when using the optical harness 104 in accordance with this invention. The quantity of light delivered to a particular switch 41 can be increased by increasing the number of optical fibers in the associated fiber optic element 102, thus conveying more light to the particular switch. Alternatively, since optical fibers of various diameters are commercially available, the light delivered to a particular switch 40 can be increased by using larger diameter optical fibers in the associated fiber optic element 102. Thus, a plurality of switches 40' can be illuminated with a single source of light 12 and various quantities of light can be conducted to the various switches of an array. Either of the aforementioned methods for increasing light would result in the associated fiber optic element 102 having a slightly larger diameter. For this reason, apertures 102 in the respective support brackets 50 and the apertures in the respective frames 100 have been deliberately made oversized. The flexibility and small diameter of the optical fibers permits the fiber optic elements 102 to be positioned in the bodies of the respective switches 40 with out interfering with the operations thereof. Furthermore the fiber optic elements 102 can be threaded through holes of small diameter, such as 103 for example, and routed around the structural contours of panel in a manner similar to that used to form a wire harness for connecting the control devices of an instrument panel into various circuits. Thus, in accordance with this invention there is provided herein a neat appearing optical harness 104 which illuminates a plurality of switches by conveying light from a single source to the various switches of an array. Because the lamp 22 is not located in the switches 40 there is no need to dismantle the switches or to use special tools when replacing the lamp 22. Since optical fibers can be obtained commercially in any length desired, the light source 22 can be disposed in a convenient location on panel 10 or in a location remote from panel 10 where it may be easily reached should replacement of the lamp be required. If it should prove necessary to use a lamp of larger size than originally anticipated, the lamp 22 can be exchanged for one of larger size without affecting the structural requirements of the switches 40. Should the lamp 22 burn out, this invention requires the replacement of only one lamp situated in a convenient location instead of numerous lamps in difficult to reach locations, as provided by illuminated switches of the prior art.

Accordingly, there has been disclosed herein a device comprising a bundle of fiber optic elements having a common end located adjacent a light source and opposite ends located adjacent the actuating portions of respective illuminated switches whereby light from a single source is conducted by each fiber optic element to illuminate an associated switch. Many modifications of the preferred embodiment may be apparent to those skilled in the art. For example, two lamps or a lamp having a dual filament enclosed in the envelope thereof may be used in place of lamp 22 to provide an alternative single source of illumination should the filament in lamp 22 burn out. Alternatively, a gas-filled lamp, such as neon for example, may

be used in place of the filament-type lamp shown. Since illumination of the gas-filled lamp is provided by ionization of the gas enclosed in the envelope thereof, a gasfilled lamp will not produce the radiant heat energy characteristic of an incandescent filament lamp. Although the preferred embodiment has been shown herein as having a lever-type switch, this invention is adapted for use with switches of other configurations, such as toggle switches,

rotary switches, slide switches, pushbutton switches, etc.

These and other modifications of this type are within the spirit and scope of this invention and, as such, are intended to be included in the claims appended hereto.

What is claimed is:

1. In combination, a plurality of electrical switches having respective transilluminative actuating members; a light source spaced from the respective electrical switches and a plurality of fiber optic elements having respective ends directed toward the light source and opposite ends directed toward respective actuating members whereby light from the source travels through the plurality of fiber optic elements to impinge on the respective actuating members and cause said actuating members to glow.

2. A combination as set forth in claim 1 wherein color filters are disposed between each of said actuating members and the respective end of a fiber optic element whereby light from the respective fiber optic elements passes through the color filters to impinge on the respective actuating members and cause said actuating members to glow with light having the color of the respective filters.

3. In combination, a plurality of electrical switches, each switch including a transilluminative actuating member adapted for displacement into one of several operating positions; a source of light spaced from the electrical switches; a fiber optic harness including a plurality of fiber optic elements having one end terminating in a common face directed toward the light source and opposite ends directed toward respective actuating members, and color filters, each characteristic of an operating position of a respective switch, movable with a respective actuating member into intervening relationship between the respective fiber optic element and actuating member, whereby light from the source travels through the fiber optic elements to pass through the intervening color filters and impinge upon the respective actuating members thereby causing said actuating members to glow with light having the colors characteristic of the operating positions of the respective switches.

References Cited UNITED STATES PATENTS 3,120,125 2/1964- Vasel. 3,163,739 12/1964 Hutt. 3,169,506 '2/ 1965 Morris. 3,177,470 4/ 1965 Galopin. 3,251,050 5/1966 Given. 3,336,456 8/ 1967 Ploetz. 3,431,410 3/ 1969 Dolan et al.

HERMAN O. JONES, Primary Examiner US. Cl. X.R. 250427; 3so 9 

